Blunt-winged Warbler

This autumn I have a bird on my target list. It’s a bird that, in reality, I probably have almost no chance of finding because, as far as I am aware, there have been only a handful of records from anywhere in the last few years – Streaked Reed Warbler. The paucity of records may be at least partly due to the lack of observers in its breeding areas (thought to be north-east China and south-east Russia) but, from recent reports from its known wintering grounds in the Philippines, this bird is declining very rapidly.

I was inspired by reading some notes from La Touche at the turn of the century who described Streaked Reed Warbler as “swarming” in late August and early September at Beidaihe. But it was more with hope than expectation that I visited Yeyahu Nature Reserve this weekend with the intention of scrutinising the reed-beds for Acro warblers.

After hearing several “tack”-ing Acro warblers that revealed themselves to be the relatively common Black-browed Reed Warbler, I discovered a singing Acrocephalus warbler.. not what I expected in September! It was difficult to pick up given the noise from the earth-movers and heavy vehicles associated with the major works ongoing at Yeyahu to make it more “tourist friendly” (more on that in a later post!). Frustratingly I couldn’t see it, despite waiting in the area for around 45 minutes. Then a Chinese Grey Shrike appeared, clearly spooked the singing bird and it fell silent. After waiting around for a while just in case it started to sing again, and with no sign, I left to cover more of the reserve but with a yellow sticky note in my mind to return later.

After covering the remaining reed-beds and finding more Black-browed Reed Warblers and several Oriental Reed Warblers, I returned to the same spot in the late afternoon. Incredibly, it (or a different bird) was singing again just a few metres from the original spot. This time, without the din of the earth-movers (they had packed up for the day), I was able to record it using my video camera. It didn’t sound like a Black-browed Reed Warbler but these Acro species can sound very similar, so I wasn’t sure.

I tried ‘pishing‘ and immediately it popped up for the briefest of moments before dropping out of sight. My impression was of a very warmly coloured bird with a strikingly white throat and lacking the well-marked face and blackish ‘brow’ of Black-browed. I pished again. Again it clambered up a reed stem and looked at me curiously.. This time I was able to rattle off a few images with the camera before it dropped again. It continued to sing from its perch out of sight. I looked at the images on the camera and immediately knew it was not a Black-browed Reed Warbler. Any other small Acrocephalus warbler would be very interesting. The likelihood was that it was either a Manchurian Reed Warbler or a Blunt-winged Warbler, both rare in Beijing. Given the bird’s warm colouration, my instinct suggested Manchurian Reed Warbler as I had found a Blunt-winged Warbler in spring at Yeyahu which was much paler than this bird. However, the face pattern – with a supercilium in front of the eye but not behind and the lack of a black upper border – fitted better Blunt-winged. The wings also looked incredibly short, also good for Blunt-winged. An email exchange with Paul Holt confirmed it as a Blunt-winged. Apparently both Manchurian Reed and Blunt-winged look much ‘warmer’ in autumn after their moult. Result!

Blunt-winged Warbler used to breed at the Summer Palace in Beijing but in recent years it has become a real rarity in Beijing. With a disjunct population, Blunt-winged Warbler is also present in parts of Central Asia and north-east India. The small population in northeast China has been the subject of speculation that it could be a different species, especially given the habitat preference seems to be different. However, my understanding is that DNA analysis has shown that they are identical.

It is certainly unusual, but not unprecedented, for Acrocephalus warblers to sing in autumn. Several of the Oriental Reed Warblers on site were still chuntering away, albeit half-heartedly.

So, no Streaked Reed Warbler (yet) but the Blunt-winged Warbler was a nice consolation! Here are a couple of images.

Blunt-winged Warbler, Yeyahu NR, 8 September 2012. Note how the supercilium is strong in front of the eye but absent behind it. In Manchurian, the supercilium should also be present behind the eye with a narrow black upper border.Blunt-winged Warbler, Yeyahu NR, 8 September 2012.

Hi Terry,
Part of the reason for its decline in the Philippines wintering areas may be habitat degradation at the most well-known site at Candaba marsh, where I looked for it a number of times in the early 2000s. I have seen it once at Beidahe on June 1st, 2008 as part of a big Acro/Locustella arrival. But where does it breed? This may be another one that is just slipping away 😦